1. Field of the Invention
The present invention generally relates to a color filter substrate and a manufacturing method thereof, and more particularly, to a color filter substrate adapted for applying in a transflective liquid crystal display (LCD) panel and a manufacturing method thereof.
2. Description of Related Art
An LCD does not emit light itself. Therefore, an LCD panel has to work together with a light source (e.g., a backlight source, a front light source, or an ambient light source), for displaying images. Light sources are utilized in different ways by different LCDs. According to the different ways of utilizing the light sources, LCDs can be categorized into three modes, transmissive, reflective and transflective. Currently, transflective LCDs are being paid of more attention, because they can work with light provided by the ambient light source and the backlight source at the same time, and thus are more suitable for portable products.
FIG. 1A is a partial cross-sectional view of a conventional transflective LCD. Referring to FIG. 1A, it shows a transflective LCD 150. The transflective LCD 150 includes a display panel 140, and a backlight module (not shown). The display panel 140 is mainly constituted by a color filter substrate 100, a pixel array substrate 112 disposed opposite to the color filter substrate 100, and a liquid crystal layer 114 disposed between the color filter substrate 100 and the pixel array substrate 112. The color filter substrate 100 includes a substrate 110 without any patterns thererin, a light-shielding layer 120, a plurality of color filter patterns 130 (only one color filter pattern 130 shown in the drawing for illustration purpose), an overcoat layer 102, and a transparent electrode 104. Each of the color filter patterns 130 includes a first pattern 130a and a second pattern 130b. The overcoat layer 102 and the transparent electrode 104 are sequentially disposed covering the light-shielding layer 120 and the color filter patterns 130. The pixel array substrate 112 includes a pixel array (only one pixel 112P is shown in FIG. 1A for illustrating the pixel array), and a peripheral circuit (not shown) coupled to the pixel array. The pixel array includes transmissive display regions T1 and reflective display regions R1 respectively corresponding to the first patterns 130a and the second patterns 130b. 
The peripheral circuit is provided for driving the pixel 112P of the pixel array, so as to allow a backlight BL′ provided by a backlight module transmitting through the transmissive display region T1 for displaying images, and to allow an ambient light EL′ being reflected by a reflective electrode 112R disposed in the reflective display region R1 for displaying images. However, light in the reflective display region R1 transmits the color filter substrate 100 for two times, while light in the transmissive display region T1 is directly emitted from the backlight source and transmits the color filter substrate for only one time. Therefore, in such a pixel 112P of the transflective LCD 150, colors of images displayed by the reflective display region R1 and images displayed by the transmissive display region T1 would be looked inharmonic.
In order to eliminate the inharmony mentioned above, the thickness of the color filter patterns 130 in the color filter substrate 100 can be adjusted, so as to form the first patterns 130a and the second patterns 130b with different thicknesses. Specifically, the thickness ta of the first patterns 130a which correspond to the transmissive display region T1 is increased, or otherwise the thickness tb of the second patterns which correspond to the reflective display region R1 is decreased. Generally speaking, the thickness ta of the first patterns 130a is substantially two times of the thickness tb of the second patterns 130b. In such a way, lights transmitting through the transmissive display region T1 and the reflective display region R1 are affected by the color filter patterns 130 for a similar degree, and thus achieving color harmony.
Typically, the light-shielding layer 120 is employed as a partition to obtain color filter patterns 130 having different thicknesses. However, the employment of the light-shielding layer 120 will cause a decrease of an aperture ratio (AR) of the transflective LCD 150, and thus affecting the entire brightness performance of the transflective LCD 150. Furthermore, although photolithography and etching processes can be used for configuring the color filter patterns 130 having different thicknesses, such steps make the process more complicated, and thus increase the production cost.
FIG. 1B is a partial cross-sectional view of another conventional transflective LCD. Referring to FIG. 1B, it shows a transflective LCD 150′ having a configuration and components similar with that of the transflective LCD 150 as shown in FIG. 1A, except that the transflective LCD 150′ does not include an overcoat layer. Each color filter pattern 130 includes a first pattern 130a′ corresponding to the transmissive display region T1 and a second pattern 130b′ corresponding to the reflective display region R1, and the first patterns 130a′ and the second patterns 130b′ have an equivalent thickness. The transflective LCD 150′ configures the first patterns 130a′ and the second patterns 130b′ with different materials. Although such a design improves the color inharmony, fabricating the color filter patterns 130′ with different materials makes the process more difficult and more complicated.